curvature versus slope
  n = 178212 
  X=0, Y = 16.48 +/- 12.33 
  Weighted least-squares fit:  Y = 22.5 + 3.660 X  + -0.03900 X**2 

slope versus dZ, curvature < 5
  n = 91833 
  X=0, Y = 8.80 +/- 4.83 
  Weighted least-squares fit:  Y = 5.8 + 0.442 X  + -0.00182 X**2 
     at X = 100, Y = 31.7 
     effective RMSE xy = 49.0 

slope versus dZ, curvature < 15
  n = 130944 
  X=0, Y = 11.55 +/- 8.45 
  Weighted least-squares fit:  Y = 6.5 + 0.381 X  + 0.00011 X**2 

curvature versus dZ, slope < 10
  n = 63844 
  X=0, Y = 9.84 +/- 5.32 
  Weighted least-squares fit:  Y = 9.0 + 0.905 X  + 0.08710 X**2 


Number of samples 179421
Max dz = 900
Mean dz = 18
RMS dz = 54.3599116997
100cm = 97.8380457137 percentile value of dz